Apparatus for casting dental fillings.



F. N WETHERBY.

APPARATUS FOR CASTING DENTAL FILLINGS.

APPLIOATION FILED MAR.27,1911.

m awo PatentgdJune 6,1911.

UNITED STATES PATENT oE IoE.

FRANKLIN N. WETHERBY, or MILWAUKEE, Wisconsin.

- Specification of Letters Patent.

Application filed March 27, 1911,. Serial No. 517,033.

ArrAmTus FOR oAsTI No DENTAL ILLINGS.

Patented June Y6, 1911;

To'all whom it may-consent:

Be it known that I, FRANKLiN N.

,WETHE'RBY, a citizen of the United States,

residing at-Milwaukee, county of Milwaukee, and State of Wisconsin, have invented new and useful Improvements in Apparatus for Casting 'Dental Fillings, of which the following is a specification.

My invention relates to improvements in apparatus for casting dental plates, fillings.

or the like, from gold and other suitable inet-als, and it pertains moreespecially,

among other things, to the device for fore-- view, and Fig. 4: is a transverse section, drawn on line a2-m of Fig. 2.

Like parts are identified by the same reference' numerals throughout the several views.

1 represents a screen cage, in and by which an investment core 2 formed of a compound of plaster of Paris and other substances, is suspended from the inwardly projecting flange 2 at a light distance from the bottom and the surrounding .walls of the receptacle 3. The screen cage 1 may be formed of perforated sheet metal, as shown in Figs. 1 and 2, or itmay be made of wire screen cloth, or other similar material, if desired.

'4; is a pattern, which in the present case represents a dental plate, and'the' same is suspended from the top of the receptacle 3 by the-vertical member 5, upwardly diverg ing member 6, and transversely arranged bars 7, which bars 7 are adapted to rest upon th upper edge of the receptacle 3, whereby thepattern is centrally suspended within the cage 1. Thepattern is preferably made of wax or'other similar substance, which is readily melted and evaporated. When the wax has been evaporated and thus withdrawn from the core, it leaves a mold by which the plate, filling or other desired object is formed from the molten metal.

In using my apparatus, the cage 1 is first eeptacle 3. When this is done, the pattern A is suspended from thetop of the ,rece tacle 3 by the transversely'arranged bars and their intermediate parts, when the cage is then filled with the investment material in a semi-fluid condition. When the investment material has remained in the cage a short time, it becomes hardened and Set ,ardund. the pattern. When this is. done, the temperature of the core is raised until the pat tern, which I have stated is formed of wax,

is entirely evaporated, thus leaving a cavity withinthe core conforming inshape to the suspended from the flange 2 within the reshape of the wax which has been .thus removed, and when this is done, the apparatus s ready for use. .The gold or. other infital is then placed in thecup shaped receptacle ,9, which has previously been formed int-he upper end of the core bythev member 6 'of' the mold. The heat is then applied to the. metal until it is melted. As soon as the metal has been melted and apartial vacuum formed, in the receptacle 3 around the core,

owing to the excessive atmospheric pressure .1

upon the upper surface of the molten metal, itis caused to quickly flow down throughthe vertical aperture 10 into the aperture -11, which has previously been formed by the wax pattern. When this is done, the apparatus and themetal therein, are permitted to cool. whereby a cast metal plate or filling is produced which exactly conforms to the shape of the pattern, which has been pre-. pared therefor.

It will be understood that the core is sufliciently porous to permit the air to be a use from, and whereby the vacuum is more quickly formed insaid aperture than it would be possible to produce the same with] the investment material supported in a more .closely fitting inclosure. j 3

It will be understood that/the receptacle 3 is adapted to be connected with a vacuumchamber through a duct 12 .and air cook 13,, from which vacuum chamber the airhas previously been exhausted and that. as soon as the metal has been melted, saidcock 1d. is opened, whereby a vacuum ii-qu ckly formed in the receptacle 3, and whereby the molten metal is caused by atmospheric pressure to quickly flow from the receptacle 9 into the aperture 11 of the core, which has previously been formed by the pattern.

Heretofore it has been common to close the mouth of the receptacle 3 with 'an air tight cover, whereby the air is excluded from such receptacle and is compelled to enter the same through the receptacle 9 and'vertical 15 vestmcnt material.

duct 10. By my improvement, however,

such cover is entirely dispensed with and.

the mouth of the receptacle 3 above and around'the screen cage 1 is sealed by the in- The so called investment material is formed of a compound of plaster of Paris, cement or other similar substances.

i Having thus descrilflid my invention, what "I claim as new, and desire to secu're by Let- 'ters la tent, is-- 1. In a deru-e. of the described class, the

combination of a. receptacle open at its upper end, a core formed of investment material, means for suspcndingsaid core from and at a distance llLltlY the upper end (it said receptacle, means for seallng'the mouth i I. i 1 1 teptaele and a VM num chain rel, .nu. means of said'receptacle above the core suspension 5 means, an exhaust duet adapted to eommunicate between said receptacle and a vacuum chamber, and an air cock for ("mt rolling the escape of air from said receptacle tdsaiil chamber. r

2. In a device ot the (lCStl'llHtl class, the

combination of a receptacle, upen' at its upper end provided at a short distance below jecting flange, a screen cagesuspended from said inwardly projecting flange; a core formed of investment material located within said cage and adapted to close and seal the mouth ot'said receptacle above said flange and cage. said core being provided at its upper end with a. cavity-tor molten metal, near its center with a mold aperture and a duct communicating hetwcensaidcavit and said mold aperture. an exhaustduct adapted to l'omi'nunieate between said ret'or controlling the escape of air from said receptacle to said ehamberl In testimony whereof l atlix my signaturein the presence of two witnesses.-

r eta' tnm N. WETIIERBY.

\Yitnesses:

JAs. ll. lunwiN, 1mm D. Barman.

so below its upper end with an inwardly pro- 

